====== MOH ======
===== General =====
  * The User Hold MoH Audio Source configured for the holder determines the audio file that will be streamed when the holder puts a call on hold, and the holdee's configured MRGL indicates the resource or server from which the holdee will receive the MoH stream.
  * Configure Multicast MOH in the private range 239.1.1.1 to 239.255.255.255
  * IP phones placed on hold join multicast IP addresses, not port numbers. Also routers will routes all the port from the same multicast address. Therefore Cisco recommends using multicast to increment on IP addresses instead of port numbers. 
  * User Hold - the only way to put on User Hold is to press the hold button
  * Network Hold - any other hold is going to be Network Hold e.g. transfer, call park --- etc.

==== MOH Format ====
In order for Cisco to be able to accept/upload a Music On Hold (MOH) file, the file must meet the specific property requirements below.

Format: WAV
Encoding: 8-bit CCITT u-Law or a-Law (stereo/mono)
Average Data Rate: 8 kbps 
Sample Rates: 8 kHz, 16 kHz, 32 kHz, 48 kHz 
Audio Sample Size: 16-bit PCM (stereo/mono)  
Channels: 1 (Mono) 

 *** CCITT uLaw, 8 kHz, 8-bit, 8 Kbps, mono ***

A good and free program to use for this is Audacity, a digital audio editor. Here's how to convert to Cisco's MOH specifications using Audacity 1.3.x.
 

  - Launch Audacity 1.3.x
  - Open the Audio File you are looking to use as an MOH file
  - Locate the Project Rate (Hz) in the bottom left corner. Set this value to 8000.
  - In the track bar, click the drop down menu and select "Split Stereo to Mono"
  - In the track bar, select "Set Sample Format", and choose "16-bit PCM"
  - Click File > Export...
  - Set the file name as desired, and verify that the File Name has NO SPACES as they are not allowed
  - Under "Save as type:" select "Other uncompressed files"
  - Click on the "Options..." button
  - Under Header select "WAV (Microsoft)"
  - Under Encoding select "U-Law"
  - Click OK and then click Save

==== Capacity Planning ====
  * Configure up to 50 audio source file and one fixed/live source via a sound card. This gives a total of 51 sources
  * 250 is the default value for unicast MOH sessions per server
  * Each multicast MOH audio source must be counted as two MOH streams
  * Maximum of 204 multicast streams (51 sources x 4 codec types)
\\
^ Server Platform    ^ Codecs                         ^ MoH Sessions Supported           ^
| MCS7815 \\ MCS7825 | G.711a/u \\ G.729a \\ Wideband | Co-resident or standalone \\ 250 | 
| MCS7835 \\ MCS7845 | G.711a/u \\ G.729a \\ Wideband | Co-resident or standalone \\ 500 | 

==== Multicast MOH from Branch router ====
  * Configure both the CUCM MOH and Branch MOH to stream using 239.192.240.1 port 16384
  * Prevent CUCH MOH from reaching the branch using either TTL 1, ACL or disable multicast on WAN interface
{{cucm-moh1.png|}}
----

==== SCCP Multicast MOH Call Flow ====
{{cucm-moh2.png|}}

==== SCCP Unicast MOH Call Flow ====
{{cucm-moh2.png|}}

==== SIP Multicast MOH Call Flow ====
{{cucm-moh4.png|}}

==== SIP Unicast MOH Call Flow ====
{{cucm-moh5.png|}}

==== SIP Media Hold Call Flow ====
  * Media hold occurs as described above when the Cisco Unified IP Phone 7905 or 7912 and third-party SIP phones place calls on hold. In addition, these phones will receive MoH if they are placed on hold by any other Cisco Unified IP Phone models.
{{cucm-moh6.png|}}

===== MOH Audio Source Selection =====
  * The MOH file played is determined by the User Hold Audio source of the device placing the call on hold i.e. the holder. 
  * The MOH server used is determined by the MRGL of the device being placed on hold i.e. the holdee.
{{cucm-moh7.png|}}

===== Configuration =====

==== Upload Media ====
  * Under **Media Resources > MOH Audio File Management**
  * The file must be in .wav format, 16bit PCM, stereo/mono, 48kHz 32kHz 16kHz 8kHz
{{cucm-moh8.png|}}

==== Configure Audio Source ====
**Static Audio Files**
  * Under **Media Resources > Music On Hold Audio Source**
  * Associate a MOH source file with a media stream
  * ID 51 is reserved for fixed audio source
{{cucm-moh9.png|}}

**Fixed Audio Sources**
  * Under **Media Resources > Fix MOH Audio Source**
  * The fixed audio source gets sourced from a fixed device that uses the local computer audio driver. It requires the Cisco USB MOH sound adaptor, which must be order separately.
  * ID must be 51
{{cucm-moh10.png|}}

==== Configure MOH Server ====
  * Under **Media Resources > Music On Hold Server**
  * The MOH server is automatically added with default values when the IP Voice Media Streaming App services are activated.
  * Max Half Duplex Streams = Max Unicast Streams
{{cucm-moh11.png|}}

===== Multicast Configuration =====

==== Audio Sources ====
{{cucm-moh12.png|}}

==== MOH Server ====
  * Under **Media Resources > Music On Hold Server**
{{cucm-moh13.png|}}

==== MRG ====
  * Under **Media Resources > Media Resource Group**
  * Check enabled multicast
    * When checked, multicast moh will be enforce for the device using this MRG
{{cucm-mrg2.png|}}


===== Service Parameters =====
  * IP Voice Media Streaming Application service
    * Supported MOH codecs (G.711, G.729a, wideband). Beware that G.729a does not sound good for music
    * QoS for MOH (signaling and audio)
    * Packet size for G.711, G.729, and wideband (20ms)
  * Call Manager Service
    * Suppress MOH to Conference Bridge (True)
    * Default Network Hold MOH Audio Source ID (1)
    * Default User Hold MOH Audio Source ID (1)
    * Duplex Streaming Enabled (False). Normally is half duplex